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121 Cards in this Set
- Front
- Back
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Where do fundamental processes of life take place? |
Inside Cells |
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All cells contain.... |
Cytoplasm- where chemical reactions happen Cell membrane- allows movement into and out of cells. Nucleus- contain genetic information and controls what the cell does. Mitochondria- respiration takes place inside these, supplying energy for cells. The larger the energy needed the more mitochondria. |
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What part of the cell structure is too small to see with a light microscope? |
Ribosomes- the site of protein synthesis. |
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What is inside the nucleus? |
Chromosomes- that carry genetic information in the form of genes. |
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What is a gene? |
It is a region of chromosomes that carry information, and controls a particular characteristic that have been inherited. |
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The order of the bases provides... |
The genetic code- that controls cell activity. |
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What do the DNA molecules do? |
form a complete set of instructions for how the organism should be constructed and how the cell should work. |
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What are chromosomes? |
long coiled molecules of DNA, divided into regions called genes. |
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What does DNA stand for? |
Deoxyribonucleic acid |
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How many pairs of chromosomes do humans have? |
23 pairs |
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What does DNA do? |
controls the production of proteins. |
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What is the DNA molecule made of? |
two strands coiled around each other in a double helix. |
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What are the genetic instructions like? |
A form of chemical code made up of 4 bases. |
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What are the 4 bases in DNA? |
A, C, G, T |
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What are the specific pairs for the DNA strands? |
A always bonds with T, C always bonds with G |
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What is the name for the specific pairing of DNA strands? |
Complementary 'base pairing' |
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Who first worked out the structure of the DNA? |
Watson & Crick. |
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Where are proteins made? |
In the cytoplasm. |
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Genes can't leave the nucleus, so how do they leave? |
A copy is made. |
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What does the sequence of bases represent the order of? |
The order the cells should assemble amino acids to make protein. |
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A group of how many bases represents one amino acid? |
3 |
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Describe the process the code goes through to make a protein. |
Code carried from DNA in nucleus to ribosomes in cytoplasm by a molecule called mRNA. DNA controls the cell function by controlling the production of proteins, some are enzymes. |
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What are the functions of amino acids? |
Structural, hormones, carries molecules enzymes. |
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What is the estimated amount of proteins in the human body? |
19,000 |
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What are enzymes? |
Proteins which act as biological catalysts. To speed up chemical reactions. |
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What can the rate of reaction be affected by? |
Temperature or pH level. |
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What is an active site for an enzyme? |
A place where only specific reactant can fit into. High temp and extreme pH can stop the lock. |
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What happens when enzyme molecules are exposed to high temperatures? |
The bonds holding the shape of the protein break. The shape of active site denature. Lock and key mechanism no longer work. |
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Enzymes work best in the human body at the optimum temperature of.. |
37 degrees |
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How to measure the rate of an enzyme-controlled reaction? |
expressed as Q10. Q10=Rate at temperature t divided by rate at temperature t - 10 |
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What are gene mutations? |
Changes to genes. Can be spontaneous. |
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Rate of mutations can be increased by ... |
environmental factors, radiation or chemicals. |
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What does a mutation do? |
Changes the base sequence of DNA. This alters the shape and function of the protein or prevents the production of the protein that the gene normally codes for. |
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What is energy needed for? |
Respiration -for muscle contraction, protein synthesis, and control of body temperature in mammals. |
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What is aerobic respiration? |
The release of energy from glucose in the presence of oxygen. |
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Where does aerobic respiration take place? |
Inside the cells. |
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Why must respiration go faster during exercise? |
Because the muscles demand more energy so respiration must release more energy. |
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Why do your pulse rate and breathing increase? |
To deliver oxygen and glucose to muscles more quickly and remove carbon dioxide from muscles quickly. |
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The word and symbol equation for aerobic respiration. |
glucose + oxygen -> carbon dioxide + water +(energy released) C6H1206+ 6O2 -> 6CO2 + 6H2O + (energy released) |
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What is respiration controlled by ? |
Enzyme-controlled, so the rate is influenced by pH and temperature. |
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When does ANAEROBIC respiration occur? |
When your muscles are working so hard that your lungs and circulatory system can't deliver enough oxygen to break down all the available glucose through aerobic respiration. |
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How does anaerobic respiration work? |
In the absence of oxygen, it quickly releases a small amount of energy through the incomplete breakdown of glucose, this means a twentieth less is released. |
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When is Lactic acid produced? |
during anaerobic respiration. |
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Describe Lactic acid |
It is relatively toxic to the cells and when it builds up in the muscles, it can cause pain (cramp) and a sensation of fatigue in the muscles. |
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What happens immediately after anaerobic respiration? |
Deep breathing continues- so oxygen is taken in to break down the lactic acid. The heart rate stays high- pumping blood through the muscles to reduce lactic acid and tp be broken down in the liver. This can be called 'repaying the oxygen debt' |
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What are multi-cell organisms? |
Complex organisms, that are large (e.g humans and animals). |
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What are the advantages of being multicellular? |
allowing organisms to be larger allowing for cell differentiation allowing organisms to be complex |
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To become multicellular,requires the development of specialised organ systems for? |
communication between cells supplying the cells with nutrients controlling exchanges with the environment |
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What does diploid mean? |
Most body cells contain two sets of matching chromosomes. |
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What does haploid mean? |
Some cells which only contain one set of chromosomes. |
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What are gametes? |
Sex cells (eggs and sperm). They are specialised haploid cells. At fertilisation, gametes combine to form diploid zygote. |
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What is sperm? |
It is a tiny sex cell with a tail that makes it very mobile. it contains many mitochondria to supply energy for swimming. |
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What does the sperm do? |
On contact with the ovum, it's acrosome, (cap-like structure on head) bursts. This releases enzymes to digest the egg cell's membrane, allowing the nucleus of the sperm, which contains the chromosomes from the father, to enter. The egg's surface changes, making it impossible for another sperm to enter. |
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Why is sperm produced and released in vast numbers ? |
because most die on the way, so it increases the chance of fertilisation. |
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When does fertilisation occur? |
During sexual reproduction (2 gametes (egg and sperm) ) fuse together. |
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Sexual reproduction in animals is? |
The joining of a sperm and an egg to produce a new, unique individual. Half the genes from each parent, because gametes have half the number of chromosomes of body cells. |
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How are new cells for growth produced? |
By mitosis |
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Cells for growth are genetically identical, the type of cell division is needed for? |
the replacement of worn-out cells repair of damaged tissue asexual reproduction. |
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Before the cell divides what does the DNA do? |
copies itself ( replication) the DNA unzips to form single strands. New double strands form by complementary base pairing. |
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What is Meiosis? |
A cell division which occurs in the testes and ovaries. The cells in these organs divide to produce gametes for sexual reproduction. So the chromosome number is halved and each cell is genetically different. This introduces genetic variation. |
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Blood has how many components? |
4 , platelets (broken cell bits, plasma, white blood cells and red blood cells. |
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What do platelets do? |
Clump together when a blood vessel becomes damaged in order to produce a clot. |
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What do plasma do? |
transports several substances around the body including foods like glucose, water, hormones, antibodies and waste products. |
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What do white blood cells do? |
Protect the body against disease. Some are flexible to engulf disease- causing microorganisms. |
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What do red blood cells do? |
transport oxygen from the lungs to the tissues. |
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Properties of a red blood cells: |
Small and flexible, so they can pass through narrow blood vessels. don't have a nucleus, so they can be packed with haemoglobin. |
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What gives the red blood cells a large surface area to volume ratio? |
The small -size and biconcave shape. |
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What happens when the cells reach the lungs? |
Oxygen diffuses into the blood. |
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The word equation for the binding of haemoglobin molecules with red blood cells. |
haemoglobin + oxygen --> oxyhaemoglobin |
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What does the blood transport around the body in? |
Arteries, veins and capillaries |
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What do the arteries do? |
transport blood away from the heart. |
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What do veins do? |
transport blood into the heart. |
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What do the capillaries do? |
exchange materials with tissues. |
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What does the right side of the heart do? |
Pumps blood which is low in oxygen to the lungs and back. |
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What does the left side of the heart do? |
Pumps blood which is rich is oxygen to the rest of the body and back. |
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Blood pumped in the arteries is.. |
under much higher pressure than in the veins. |
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How much of a circulatory system do mammals have? |
Double, two loops |
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The advantage of a double circulatory system is? |
Blood pumped to body at higher pressure than pumped to the lungs. A much greater of flow to the body tissues. |
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What adaptations do arteries, veins and capillaries have to help with their function? |
Arteries- cope with high pressure of blood, so they have a thick wall made of elastic muscle fibres. Veins- have lumen is bigger compared to thickness of walls. They have valve to prevent backflow of blood. Capillaries- have thin permeable walls, to allow exchange of substances between cells and the blood. |
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The wall of the heart is mostly made of muscle, there are 4 main chamber: |
Left and right ventricles Left and right atria. |
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What do ventricles do? |
contract to pump blood out of the heart. The right pumps to lungs and back. The left is under pressure around the whole body. |
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What does the Atria do? |
receives blood coming back to the heat through the veins. |
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What do semilumar, tricuspid and bicuspid valves do? |
Make sure that the blood flows in the right direction. |
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What do plant cells have that animal cells don't? |
Chloroplasts, a cellulose cell wall to provide support. And a vacuole which contains cell sap and provides support. |
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To see the parts of a plant cell.. |
Peel with tweezers a layer of skin tissue from onion. Place under microscope Add a drop of iodine to the tissue and cover the slide with a coverslip. Look at onion cell at x100 |
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What do bacteria cells lack? |
A true nucleus , mitochondria and chloroplasts |
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What is growth a measurement of? |
Increase of height or mass. |
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What does growth involve? |
Cell division and cell differentiation |
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How do animals grow? |
By increasing the number of cells. The cells specialise or differentiate into different types of cell at an early stage to form tissues and organs. |
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Difference between animals and plant cell growth. |
animal cells lose ability to grown after a finite size but plants can continue. |
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Plant division is mainly restricted to? |
Meristems at the roots and tips |
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The two main stages of growth in humans? |
just after birth and during adolescence |
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Advantages of length/height method, wet weight method and dry mass method. |
Easy and rapid measurement Not destructive, is relatively easy to measure Most accurate method |
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Disadvantages of length/height method, wet weight method and dry mass method. |
increase in mass might occur with no increase of height. water content of living tissue can be variable and may give a distorted view overall. Destructive as removal of water kills organism. |
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What are stem cells? |
undifferentiated animal cells, which can specialise and develop into different cells, tissues and organs. |
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Where can stem cells be obtained from? |
Embryonic tissue |
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What is selective breeding? |
animals or plants with favourable characteristics are deliberately selected and crossbred. This is to produce offspring with desired characteristics. It can take many generations to get a desired result. |
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Selective breeding can contribute to improved agricultural yields in animals and crops for example : |
Quantity of milk - cows selected to produce high volumes of milk daily. Quality of milk - Jersey cows selected to produce rich and creamy milk Beef production- some cattles are selected for characteristics like early maturity (hardiness) and high number of offspring.1 |
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Disadvantages of selective breeding |
Reduces the gene pool Number of different alleles in population Less variation Lack of variation can lead to harmful characteristics in-breeding |
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What is genetic engineering/modification? |
All living organisms having the same genetic code, so genes can be artificially transferred form one organism to another. |
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Altering genetic make-up of organism can be done for many reasons... |
To improve crop resistance to frost damage, disease or herbicides. Improve the quality of food Produce a required substance |
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Advantage of genetic engineering |
Allows organisms with new features to be produced rapidly. |
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Disadvantage of genetic engineering |
The inserted genes may have unexpected harmful effects. |
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Ethical benefits of genetic engineering |
producing disease-resistant crops and higher yields to feed population. creating crops that will grow in poor dry soil to feed people in poor areas. potentially replacing faulty genes to reduce certain disease. |
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Ethical Concerns of genetic engineering |
Plants may cross-breed with wild plants and release their new genes into environment Foods may not be safe to eat in long term Lead to genetic make-up of children Children with born faults could be aborted Insurance companies could turn down people |
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Principles of genetic engineering |
Selected isolated and removed using enzyme gene is inserted into genome organism replicates |
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What is gene therapy? |
changing a person's genes in an attempt to cure disorders |
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What does gene therapy do? |
Can involve body cells or gametes. This can alter offspring life |
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What is asexual reproduction? |
Produces identical copies in the absence of sex cells and fertilisation e.g spider plants, strawberry plants and potato plants |
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What are clones? |
Plants grown from cutting or tissue culture. If the plant has desirable characteristics it can be reproduced by taking stem, leaf or root cuttings. |
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Advantages of cloning commercially |
Cloned plants will be genetically identical to parents, so all characteristics will be known. It is possible to mass produce |
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Disadvantages of cloning commercially |
any susceptibility to disease or sensitivity to environment, will affect all the plants Reduction in genetic variation reduces the potential for further selective breeding |
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How plants tissue culture can be cloned |
Select parent plant with desired characteristics Scrape off a lot of small pieces of tissue into breaker containing nutrients and hormones. This must be done without the presence of bacteria. New plants will grow. |
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What is cloning an example of ? |
Asexual reproduction which produces genetically identical copies. Identical twins are naturally occurring clones. |
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Cloning example of animal |
Dolly the sheep, first mammal successfully cloned using a technique called embryo transplantation. Dolly was produced by process of nuclear transfer. Nucleus of a body cell from wanted cheep into empty egg cell with nucleus removed. Short electric current made cell divide then put into another sheep to grow. |
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Uses of cloning |
Possible to clone human embryos in same way that animals are. Mass production of animals with desired characteristics Genetically engineering to provide human products. |
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Ethical dilemmas with cloning humans |
Unreliable Limited life span and die early Mental and emotional development on human not known Religious views Controversial |
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Benefist of cloning |
All have same characteristics Sex and birth can be controlled Egg and sperm donation cows kept and carriers |
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Riskc of cloning |
Reduces genetic variation Identical copies , disease could wipe all out May not be healthy or live normal lives |
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Animal Organ Donors |
Genetically engineered to be accepted on human organ donor list. Could be cloned to produce supply. Cn |
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Concerns of animals for organ donors |
Infection might be passed Ethical issues concerning animal welfare and rights |
